1. Field of the Invention
This invention relates to a brushing station for a labelling machine for labelling bottles and the like. The labelling machine has a turntable located between a feeder star wheel and a discharge star wheel. The turntable has a rotating, un-hooded or non-hooded bottle support positioned on a substructure, and receptacles for receiving the bottles along its circumference. At least one brush element is located along the circumference of the turntable. Each bottle receptacle has a motorized rotary plate and a bottle centering head that is supported by a radial cantilever arm. The cantilever arm, in turn, is supported on a column that is mounted on the bottle support and is axially moved or adjusted by an actuator. Both the rotation drive mechanism that rotates the rotary plate and the actuator that moves the columns are cam driven devices. Each cam driven device has a common, stationary cam positioned in the substructure for operating the cam drives of the rotation drive mechanism and the cam drives of the actuator.
The labelling machine includes a pressing station for metal foil sheets placed around the top and the neck of the bottles. A transfer station is located on the turntable that transfers the metal foil sheets to the bottles. Also provided is a delivery star wheel having bell-shaped pressing elements that can be moved axially by a cam controlled drive mechanism toward the bottle top. The pressing elements are held by a support located above the delivery star wheel and rotates with the delivery star wheel.
2. Background Information
Labelling machines having unhooded, or non-hooded, bottle supports are known. See, for example, German Patent No. 391 729 and French Patent No. 1,294,574. In comparison with other labelling machines having a hood located over the bottle supports to support the centering heads and their drive mechanisms, the non-hooded labelling machines have the advantage of easier access for servicing and maintenance. Nevertheless, the majority of the labelling machines in current use have a hood over the bottle support, primarily because when there are a great many receptacles, it is easier to adjust the height of all of the centering heads at once when changing from one format to another.
One labelling machine of the prior art, as disclosed in French Patent No. 1,294,574, has each column mounted in a guide sleeve located on the bottle support. The brush elements are located both on the inside and on the outside of the circulation path of the bottles. While it is possible to easily achieve a stationary fastening of the outside brush elements, the stationary fastening of the inside brush elements is difficult because of the rotating parts in the inner region of the support. The prior art does not propose any possible solutions to this problem.
An additional feature of prior art labelling machines is that restoring springs are employed to operate the cam-controlled movement of the centering elements. These restoring springs are provided to hold the engagement elements of the cam-controlled transmissions against the cam. That is possible, however, only if the amount of spring force is provided as a function of the mass acceleration forces which are present. Since the restoring springs must move the engagement elements, the columns, the cantilever arms and the centering heads, correspondingly large springs are required to produce even small forces.
On such pressing stations, the rotating paths of the delivery positions of the turntable and of the delivery star wheel overlap so that the bottles can be transferred in synchronization from the turntable to the delivery star wheel. Since, during transport of the bottles both in the turntable and in the delivery star wheel, elements such as centering heads grip the tops of the bottles when the bottles are on the turntable and pressing elements grip the tops of the bottles when the bottles are on the delivery star wheel, it is difficult to achieve a collision-free fit of the elements of the turntable and of the delivery star wheel in the overlapping region. Also, for purposes of transferring the bottles from the turntable to the delivery star wheel at the proper angle of rotation, the bottles in the turntable must be held as long as possible in a rotation-free manner by axial bracing between the turntable which supports the bottom of the bottle, and the centering element which grips the top of the bottle. For a collision-free passage of the pressing elements of the delivery star wheel, it is necessary to move the pressing elements out of the overlapping area during the passage.
In German Laid Open Patent Appln. No. 31 04 807 C2, which corresponds to U.S. Pat. No. 4,414,056, this problem is approached by equipping each pressing element so that it can pivot to one side from its position above the receiving position, into a position which lies outside the portion of the turntable traversed by the centering head of the turntable. Only when the pressing element has passed the overlapping area can it be pivoted over the bottle top of the corresponding receiving position, and then lowered to press the foil sheet. One disadvantage of such pressing stations is that a great deal of space is required for the pivoting movement, and the drive and transmission mechanisms required for the pivoting motion and the subsequent axial movement are quite complex and expensive.
These disadvantages related to the pivoting movement do not occur on another pressing station disclosed in German Laid Open Patent No. 35 15 730 A1. In that patent, the pressing elements are located so that they pivot on the circumference of a support that has a smaller diameter than that of the delivery star wheel, and is mismatched in relation to the delivery star wheel. With that configuration, the path of the pressing elements lies outside the path of the receiving positions of the turntable and only above a short segment of the path of the receiving positions of the delivery star wheel. A disadvantage, however, is that synchronization between the receiving positions of the delivery star wheel and the pressing elements can only be achieved over the above-mentioned short segment, and then only approximately, which has a negative effect on the quality of the pressing of the foil sheet.
On the pressing stations described above however, a collision-free passage of the pressing elements on the delivery star wheel and the centering heads on the turntable or synchronization between the receiving positions of the delivery star wheel and the pressing elements is only guaranteed during operation when there is no jamming up at the outlet of the delivery star wheel. To prevent major damage to the pressing station when there is a jamming up at the outlet of the delivery star wheel, the delivery star wheel is coupled with the drive by means of a slip clutch. If a jamming up does occur, then the delivery star wheel can slip in relation to the drive. That construction requires pivotable pressing elements which are oriented concentrically to the receiving positions causing the synchronization between the turntable and the pressing elements is lost. When rotation continues, therefore, even with the pressing elements pivoted back, collisions may occur. In the other pressing station of the prior art described above, with the support for the pressing elements offset and not torsionally connected to the delivery star wheel, a slipping of the delivery star wheel in relation to the drive as a result of a jam leads to an offset between the receiving positions and the pressing elements corresponding to the receiving positions in the pressing area. Once again, the result is that the pressing elements can no longer be placed centrally over the bottle tops.